As a method for producing a toner, which contains a color former compound, a color developing agent, and optionally a decolorizing agent and is capable of erasing an image formed on a recording medium by decolorization (erasing the color), a kneading pulverization method is usually adopted. The kneading pulverization method is a method for producing desired toner particles by melt-kneading a binder resin, a color former compound, a color developing agent, a release agent such as a wax, a charge control agent, and the like, cooling the resulting kneaded material, finely pulverizing the cooled material, and then, classifying the resulting fine particles.
However, although the reduction in the particle diameter of a toner is demanded for achieving a high-quality image, there is a limit to the reduction in the particle diameter by a kneading pulverization method.